Created test and method to shuffle array.

Author: Johannestegner

src/Util.js

@@ -0,0 +1,15 @@
+export const shuffle = (list) => {
+  const copy = [...list];
+  let i = copy.length;
+  let temp = null;
+  let rI = null;
+
+  while (0 !== i) {
+    rI = Math.floor(Math.random() * i);
+    i--;
+    temp = copy[i];
+    copy[i] = copy[rI];
+    copy[rI] = temp;
+  }
+  return copy;
+};

test/Util.test.js

@@ -0,0 +1,11 @@
+import { shuffle } from '../src/Util';
+
+describe('Tests for the shuffle util function.', () => {
+
+  test('Shuffle randomizes order in array.', () => {
+    const array = ['a', 'b', 'c', 'd', 'e'];
+    const shuffled = shuffle(array);
+    expect(shuffled).toEqual(expect.arrayContaining(array));
+    expect(JSON.stringify(shuffled)).not.toStrictEqual(JSON.stringify(array));
+  });
+});